Electronic positioning method and apparatus

ABSTRACT

Disclosed are a method and apparatus for determining the deviation of an image from a predetermined position on a kinescope screen. This method and apparatus is useful, for example, in centering an image on the screen. The scan lines of the kinescope are divided into a series of pulses. The pulses within the image on each side of a reference line or X-Y coordinate system are counted and compared. The ratio of the pulses is an indication of the area of the image on each side, and suitable adjustments may be made in the position of the image to center it with respect to the reference line.

DESCRIPTION Technical Field and Background

This invention relates to a method and apparatus for electronicallypositioning an object viewed by a television camera in the center, or ata selected coordinate position, of the television receiver screen.

In my copending application filed of even date herewith, there isdisclosed and claimed a method and apparatus for electronicallydetermining the relative size of areas which are brought individuallyinto the field of view of a television camera, such areas having acontrasting background.

The method and apparatus according to that invention has particularapplication in the determination of sizes of bright areas against a darkbackground or vise versa, especially illuminated areas such as holesthrough a plate, e.g., spinnerette holes. In the instance of spinneretteholes, the tiny holes through which liquified polymer is spun should beapproximately the same size and essentially free from defects such asbeing out of specified shape, clogged, etc. Such method comprises

(a) generating a video signal of at least a single frame duration whichincludes the bright image such that the complete area to be measured isencompassed,

(b) applying the electrical signal representing the bright image to aswitching device, one input of which is supplied with a switching signalhaving a frequency of at least 10 times the line scan frequency of thevideo signal to divide the period of scanning represented by the brightimage into a series of pulses, the duration of the pulse series beingcontrolled by the beginning and ending of the signal representing thebright image, and

(c) electrically applying the output signal from the switching device toa digital counter, whereby the area of the bright image is measured interms of number of pulses counted.

The present invention provides a method and apparatus for positioningthe image to be viewed at a selected coordinate position on thetelevision screen.

DISCLOSURE OF INVENTION

According to the present invention, there is provided apparatus andmethod of determining the deviation of an image from a predeterminedposition on a kinescope screen, the image having a contrastingbrightness with respect to the rest of the picture area comprising thesteps of

(a) generating a video signal of at least a single frame duration whichincludes the bright image such that the complete area to be measured isencompassed,

(b) electrically applying the video signal to a quantizer having theability to pass portions of the video signal above a predeterminedamplitude which correspond to the bright image, and to reject portionsof the video signal below the predetermined amplitude,

(c) amplifying the output signal from the quantizer to a levelsufficient to trigger a digital logic element,

(d) applying the electrical signal representing the bright image to aswitching device, one input of which is supplied with a switching signalhaving a frequency of at least 10 times the line scan frequency of thevideo signal to divide the period of scanning represented by the brightimage into a series of pulses, the duration of the pulse series beingcontrolled by the beginning and ending of the signal representing thebright image,

(e) electrically applying the output signal from the switching device toa digital counter, whereby the area of the bright image is measured interms of number of pulses counted,

(f) forming at least one line of a X-Y coordinate system on thekinescope screen to establish a reference position by intensifyingpredetermined pulse counts of said switching signal to form the line,

(g) using the predetermined pulse counts as a switching device to turnoff or on the scan lines on one side of said coordinate line, and

(h) counting the dots to one side of the line, whereby the area of theside is determined in terms of dot count and the ratio of such dot counton one side of the line to the dot count for the entire bright image canbe used to determine position of the bright image area with respect tothe line.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is schematic view of the measuring apparatus;

FIG. 2 shows preferred circuitry for using a video signal to determinethe size of a bright area having a darker background;

FIG. 3a is a representation of a kinescope displaying the image of aspinnerette hole; and

FIG. 3b is an enlarged representation of portions of scan lines brokeninto a series of dots used in the measurement of bright areas.

FIG. 4 is an elevation view of apparatus for supporting and positioningwork pieces for viewing by a television camera in accordance with thepresent invention;

FIG. 5 is a plan view of the supporting and positioning apparatus shownin FIG. 4;

FIG. 6 is a sectional view taken along lines 6--6 of FIG. 4;

FIG. 7 is a sectional view taken along line 7--7 of FIG. 4;

FIG. 8 is a diagram of preferred electrical circuitry for electronicallypositioning work pieces at a predetermined coordinate position withrespect to the television receiver screen;

FIG. 9 is a diagram of a preferred electrical gating system;

FIG. 10 is an elevation view of a television screen illustrating thepositioning method according to this invention; and

FIG. 11 is a diagram illustrating simplified circuitry for centering animage.

DETAILED DESCRIPTION OF THE INVENTION

According to this invention, area measurements are made of illuminatedportions of objects in the manner illustrated in the drawings. Forpurposes of explanation, the apparatus and method will be described withreference to a spinnerette plate which contains a number of holes,although it will be obvious to those skilled in the art that theinvention may be used for other purposes as well.

Referring to FIG. 1, a spinnerette plate 10, containing a plurality oftiny holes 12 is mounted on an assembly having provisions for movementin the "X" and "Y" directions so that the plate may be automaticallymoved from position to position for sequential measurements of holes.Apparatus for providing such movements will be obvious to those skilledin the art. A preferred apparatus (FIGS. 4-7) includes a pair ofcooperating motion translators mounted at 90° angles to each other so asto cooperate in producing movements in the X and Y directions. Themotion translators cause the plate 10 to travel in precise longitudinalmotion and may be driven by stepping motors. Thus, by the cooperation ofthe two motion translators, the plate 10 may be moved with precision topredetermined X and Y coordinate positions.

Commercially available motion translators include Series B6000 Unislide,sold by Velmex, Inc. of East Bloomfield, N.J. Suitable commerciallyavailable stepping motors are Slo-Syn Translator Type ST105 ModelM093-FD301 available from The Superior Electric Company of Bristol,Conn.

The stepping motors are preferably operated from a computer which hasbeen programmed to move the plate 10 in successive steps to the X and Ycoordinates of selected holes. As well known in the art, a suitablecomputer may be programmed with the location of each hole in the plate.Subsequently, the program may be used to return the plate to X and Ycoordinate positions for sequentially inspecting the holes.

Plate 10 is supported within the field of view of television camera 40.A light source 42 directs a columned beam of light rays 44 at plate 10.For convenience, a mirror 46 may be placed in the path of the light raysto direct them coaxially with the holes 12. The television camera thuspicks up the rays of light which pass through holes 12 in aperpendicular direction when the plate is correctly positioned. When theapparatus is used to measure the size of very tiny holes 12, it may bedesirable to use a magnifying device to expand the beam of light tooccupy a large portion (preferably at least 50%) of the field of view ofthe camera.

The television camera, as is well known, scans the image formed thereinto provide an electrical current output (known herein as a "video scanoutput signal" or a "scan output signal"), which in the camera producesa scan output signal of high amplitude corresponding to the bright areasand low amplitude corresponding to the dark areas. The scanningprogresses line by line down a frame with the video scan outputportraying the scanned results of each line serially from the top to thebottom of the frame with the scan signals for each line separated byline synchronization pulses, and so on from one frame to the next, withthe frames separated by frame synchronization pulses known as "framesync pulses". The television camera conventionally scans, in one field,every second line of those required to completely scan the image, andthen scans the omitted lines in the next field.

The video signal generated by camera 40 is fed to a quantizer 60 whichfunctions to pass portions of the video signals which are above apredetermined amplitude corresponding to the light areas of the pictureand reject portions of the video signal below the predeterminedamplitude corresponding to the darker area of the picture. Thus, onlythat part of the picture representing the light area to be measured ispassed by the quantizer 60. Such quantizers are commercially available,for example, CVI Model 606A Video Quantizer, a product of ColoradoVideo, Inc. The quantizer is capable of separating the area to bemeasured (light area) from the rest of the relatively dark picture. InFIG. 3a, there is illustrated a picture that would appear at thetelevision monitor. The light area 62 representing light passing throughthe spinnerette hole is passed by the quantizer while the darker area 64is rejected.

The signal from the quantizer is fed to an amplifier 66 and then to oneterminal of NAND gate 68. A synchronization (sync) pulse from a syncgenerator 74 is fed to another terminal of NAND gate 68 and then is fedto a digital counter 70. Television receiver 72 is used to monitor thepicture to insure proper positioning of the camera to encompass thecomplete area to be measured and proper size of light areas. NAND gate68 is effective to pass a signal when at least one of the inputterminals has no signal. Conversely, when there is input to allterminals there is no output. Thus, the electrical signal representingthe bright portion of the picture is applied to the NAND gate switchingdevice, and another input is supplied with a switching signal fromcounter 75.

The sync generator may conveniently be crystal controlled, and producesa signal having a frequency of about 20 MHz, which is then divided bytwo by counter 75, the output of which is applied to an input of gate68. This results in a frequency of at least 10 times the line scanfrequency of the video signal. A signal of 10 MHz pulses becomesavailable every time a signal is available from the quantizer to formthe vertical lines. The line scans are broken into a series of pulses 74by the 10 MHz signal applied to the gate 68 in the light area 62. Eachhorizontal line scan is converted into a burst of pulses which areavailable every time the beam scans where light from the spinnerettehole is present. It is the counting of these pulses, suitably by adigital counter, which gives a measure of the size of hole.

In a conventional television signal there are 525 scan lines per frame.The duration of each scan line is about 1/15,750 second. The beginningof each scan line is controlled by a sync pulse from the sync generator.In accordance with the present invention, a crystal oscillator in thesync generator 74 is also used to produce 20 MHz pulses which would actto switch each scan line off and on about 600 times, if the entirehorizontal extent of the line were in a light area. The number ofswitching pulses accumulated in each scan line is counted, preferably bya commercially available electronic counter, and the total is used as areference for a hole of a known size. By simple mathematicalproportions, the total number of switching pulses counted inmeasurements can be related to sizes of other holes.

Since the video signal is not continuous, but consists of a series ofscanned images rapidly repeated, it is necessary to separate those scansto form a single television picture. To accomplish this, additionalsignals produced by the sync generator are employed to show thebeginning and end of each complete scan. Specifically, a vertical syncpulse (60 per second or twice for each complete television picture) isused. Thus, when the counter 70 is activated by applying a first triggerpulse to its gating system, the counter accepts the first vertical syncpulse which it receives. The counter continues to receive the pulses,skips the second vertical sync pulse and when the third is received(indicating a complete frame), the counter activates its own gatingsystem to disable itself so that no more counts can be accumulated.

A counting or measuring cycle is initiated when switch 80 is put inposition A, grounding the input of inverter 82 and causing the inverter82 to give an output of positive voltage. This voltage is applied tothree-decade digital counter 70 and causes the counter to reset to 0.When the switch 80 is flipped in the opposite direction into position B,it causes flip-flop 84 to be actuated which prevents bouncing of switch80.

Once the flip-flop 84 has been flipped by the switch, it applies avoltage to counter 86 which divides the pulses by 10, having a binarycoded decimal output which must be converted into a 10-count signal.When the first pulse comes into counter 86 it turns the decoder 88 offof 0 and turns on a voltage to position 1. This voltage is translatedthrough inverters 90 and 91 which share a common resistor 92 and cause avoltage to be developed across that resistor. This voltage is applied tothe third input terminal of gate 68 so that there is now a positivesignal on all three inputs. The video signal from amplifier 66 then iscapable of going through the gate. The counter signal going into thegate is switching off and on. This causes the video signal to be brokeninto pulses and the third signal, which came from decoder 88 through theinvertors 90 and 91 now permits the other two signals to be passedthrough gate 68 for the duration permitted by decoder 88 (two counts),representing one picture frame. Since there are two vertical sync pulsesfor one picture frame, counter 70 then receives a video signal which isdivided into pulses for the duration of one picture frame. The signalwhich is coming from resistor 92 is then turned off and no other signalscan come through the gate 68. The reading on counter 70 is stored untilsuch time as switch 80 is flipped back to position A and erased. Voltageis applied in the appropriate direction back to flip-flop 84 and causesflip-flop 84 to be automatically reset and ready for the next pulse thatis applied. When switch 80 is repositioned to B again, another sequenceof pulses may be applied.

Referring to FIGS. 4 and 5, a spinnerette plate 10, containing aplurality of tiny holes 12 is mounted on an assembly having provisionsfor movement in the "X" and "Y" directions so that the plate may beautomatically moved from position to position for sequentialmeasurements of holes. Apparatus for providing such movements will beobvious to those skilled in the art. The apparatus illustrated includesa pair of cooperating motion translators 14 and 16 mounted at 90° anglesrelative to each other so as to cooperate in producing movements in theX and Y directions. Translator 14 is fixed to the top of translator 16.Plate 10 is secured to mounting bracket 18 of translator 14. The motiontranslators 14 and 16 include movable supports 20 and 22 respectivelywhich are caused to travel in precise logitudinal motion along threadedshafts 24 and 26 respectively and are driven by stepping motors 28 and30 respectively. The stepping motors 28 and 30 are connected to threadedshafts 24 and 26 respectively and designed to provide small rotationalmovement thereto. Thus, by the cooperation of the two motiontranslators, plate 10 may be moved with precision to predetermined X andY coordinate positions.

Commercially available motion translators include Series B6000 Unislide,sold by Velmex, Inc. of East Bloomfield, N.J. Suitable commerciallyavailable stepping motors are Slo-Syn Translator Type ST105 ModelM093-FD301 available from The Superior Electric Company of Bristol,Conn.

The stepping motors are preferably operated from a computer which hasbeen programmed to move the plate 10 in successive steps to the X and Ycoordinates of selected holes. As well known in the art, a suitablecomputer may be programmed with the location of each hole in the plate.Subsequently, the program may be used to return the plate to X and Ycoordinate positions for sequentially inspecting the holes.

Plate 10 is supported within the field of view of television camera 40.In a typical application, the supports 20 and 22 have a total freetravel of six inches in which the supports are propelled on gibbed metalways by means of threaded shafts incorporating 40 threads per inch. Theshafts are directly connected to the stepping motors connectedelectrically to step 1/200 revolution for each electrical pulse appliedto the motor windings.

As can be readily determined by mathematical analysis of therelationships between the amount of circular travel exhibited by thestepping motor for a single driving pulse, and the number of treadsmachined on the lead screw, one driving pulse produces a movement of0.00125 inch travel for the table being driven by the screw. Thus bycounting the pulses which are applied to the motors driving eachsupport, it is possible to precisely move each table a predetermineddistance along its ways.

The motors turning the shafts 24 and 26 are supplied with electricalpulses applied to their stator windings by means of electrical poweramplifiers called translators. Small voltage signal pulses ranging froma logical zero level of about 1.0 volt to a logical one level of about4.5 volts are applied to the inputs of these translators. Eachtranslator is equipped with two inputs. One input when supplied withlogic pulses causes the motor to rotate in a counterclockwise direction.The second input when supplied with logic pulses causes the motor torotate in a clockwise direction. Only one input is activated by logicpulses at the same instant, since simultaneous activation of both inputsresults in a counterproductive reaction which produces no movement ofthe motor.

A microcomputer is used to provide the logic pulses which wereintroduced into the inputs of each translator. The microcomputertypically used for this purpose is an Intel type 80/30 centralprocessing unit fitted with auxiliary memory of 16,000 bytes of RAMmemory and auxiliary input and output ports sufficient to permittransmitting the electrical pulses produced by the computer to thetranslator inputs.

Electrical pulses of the nature required to activate the inputs of thetranslators can be produced by any of several ways. A variable frequencyoscillator can be used. A crystal stabilized oxcillator can also beused. Simple manual switching can be used, and the electrical pulseswhich combine to form the numerical output of a digital computer can beused. In order that programmed time control of the number and rate ofpulse production could be achieved, this latter method is preferred.

The Intel 80/30 microcomputer can be programmed using either of twomethods. The first used is that of a "high level" language such as"basic". This is a commonly used programming language widely used bythose practicing the computer art. The second language used is dubbed"machine" language. Choice of the appropriate language must be based onthe end use to which the computer is directed. Basic programminglanguage offers simplicity in programming but is restricted in that itsuse requires considerable time for the computer to perform its logicduties. Machine language is more difficult to employ, but offers greatspeed of execution on the part of the computer. Analysis of the problemsof causing the stepping motors to propel the tables at acceptable speedsmade it evident that machine language is preferred to produce the pulsesand the counting of the pulses to ration out the extent of travel of thetables. Because facility of command for the movement of the tables isrequired, basic language is used to program those temporary commandswhich are required to fit the travel pattern of the tables to the taskswhich they were required to do. In this instance that task is to move aspinnerette of oblong shape in both X and Y directions stopping motionto permit a television area determining device to determine the areaopen for each hole drilled or otherwise produced in the spinneretteplate.

Programming consists of determining the extent of travel required totranslate the spinnerette so that upon stopping of the motion a holewill be positioned directly under the area determining device. This isdone by reducing the interhole dimensions to pulse counts to activatethe table motors, and programming them into the computer. The rate atwhich the pulses are produced requires adjustment so that initialmovement of the motor and attached table is effected by slow generationof pulse with a gradual increase in pulse production until the maximumpulse rate which is acceptable to the motor is attained. Stopping themotor requires the reverse action, i.e., gradual decrease of pulse rateuntil the final pulse is delivered. Machine language of the computer toeffect this routing is prepared and programmed as is well known by thoseskilled in the art of computer programming.

Upon programming the system described and attempting to use it todetermine the area of holes drilled into a spinnerette, it is discoveredthat errors in manufacture of the spinnerette result in the holes beingplaced inexactly, so that precise movement of the tables does not resultin proper positioning of the holes under the area determining device. Todetermine whether a hole is off center, and if so, by how much, thetelevision screen containing the image of the spinnnerette hole iselectronically blanked off so that any image existing on one side of thevertical or horizontal center lines are screened off, and the area ofthe remaining image is measured and a comparision made to the area ofthe total image shown on the screen when the image is not blanked off.Since centering is required, a condition such that the ratio of blankedoff to unblanked off image would be equal to one, or equal to one-halfof the total image would represent the ideal centered condition. Anyratio other than the one satisfying this condition is then compared withthe ideal and the difference registered as insufficient (negative) orexcessive (positive). The excess or insufficiency of area determined inthe blanked off image condition then becomes a factor in establishingthe number of driving pulses to be applied to turn the stepping motorsto advance the spinnerette to the next hole, or to adjust the motorforward or backward to attain perfect centering of the hole under thetelevision camera. The positive or negative nature of the area woulddetermine which direction the motor would be required to turn in orderto attain the desired centered condition.

For rapid processing of the spinnerette, centering should beincorporated into the subsequent move to be made after an out of centercondition is determined by the television camera area determiningsystem. The number of pulses to be substracted or added to the pulsesrequired to move the spinnerette to the next hole would then bedetermined by the computers processing of the signals to it and thecentering correction applied to the next hole. Assuming thatmanufacturing specifications of the spinnerette have not beenexcessively violated, the next hole should arrive under the areadetermining device reasonably well centered.

The apparatus and method for determining the deviation from the centerof the TV screen of hole images will now be described with particularreference to FIGS. 8 and 9.

The electronic systems for sending correction pulses to stepping motors28 and 30 in synchronized to a 20 MHz oscillator 100 which driveshorizontal sync pulse generator 101 and vertical sync pulse generator160. The 20 MHz signal from oscillator 100 is counted and converted intohorizontal synchronization frequencies of 15,750 Hz by horizontal syncpulse generator 101. The 20 MHz pulses are also counted and divided bytwo by decade counter 102 which has a binary coded decimal output. Thus,the output of counter 102 is 10 MHz. These 10 MHz pulses are againcounted by a group of three type 7490 decode counters 104, 106 and 108which also have binary coded decimal outputs. These outputs are decodedby type 7442 four-to-ten line binary coded decimal-to-decimal decoders110, 112 and 114 respectively. The outputs of the decoders are selectedto provide a decimal output of 3-1-4.

Each pulse represents one significant digit and place of the number3-1-4. The pulses serve to form a vertical line 105 (see FIG. 10) in thecenter of the TV screen, or each scan line is broken up into 628 dots bythe imposition of the 10 MHz signal. Vertical line 105 is formed bycontrolling the intensity of the electron beam of the kinescope.Modulation of the video signal applied to the kinescope monitor isapplied at a 10 MHz rate and the modulated video signal is gated by thepulse produced from the output of gate 116. Thus, the electron beam ofthe kinescope is turned on to permit a signal pulse of each scan line ata 10 MHz rate to illuminate the screen at the center. The 3-1-4 digits,when activated, provide zero logic pulses which must, in order to beaccommodated by type 7410 NAND gate 116, be deconverted into logicalones. This is accomplished by three type 7404 invertors 118, 120 and122. When all three of the digits 3-1-4 which are selected from theoutputs of the decoders 110, 112 and 114 provide logical ones to gate116, the output of gate 116 produces a logical zero. This logical zerois fed to a pair of type 7400 NAND gates 124 and 126 which are arrangedto provide a flip-flop 128. The imposition of a logical zero on theinput of gate 124 causes its output to produce a logical one, which inturn activates the input of NAND gate 126, causing it to produce anoutput of a logical zero. There is, in effect, a switching actionproduced between gate 124 and 126. Once they have been put into a statewhere the input from gate 124 has gone to a logical zero, gates 124 and126 tend to stay that way until such time as they are restored by meansof a reset signal derived through type 7404 invertor 130 from syncgenerator 101. Upon production of a horizontal sync pulse having alogical one, invertor 130 converts this to a logical zero and applies itto gate 126 causing flip-flop 128 to reset. The signal output fromflip-flop 128 is a symmetrical wave in which half the period duringsuccessive horizontal drive pulses the wave form is logic 1 and theremaining half is zero. This wave form is used to switch the video beamof the kinescope on or off at the vertical center line 105, as shown inFIG. 10.

Oscillator 100 also drives vertical sync pulse generator 160. The 20 MHzsignal from oxcillator 100 is counted and converted into verticalsynchronization frequencies of 60 Hz. These 60 Hz pulses are againcounted by a group of three type 7940 decode counters 132, 134 and 136which also have binary coded decimal outputs. These outputs are decodedby type 7442 four-through-ten line binary coded decimal-to-decimaldecoders 138, 140 and 142 respectively. The outputs of the decoders areselected to provide a decimal output of 1-2-8 to thereby produce pulseswhich serve to form a horizontal line 107 (see FIG. 10) in the center ofthe TV screen. Thus, line 107 of one frame and its counterpart fill-inline of the next frame are highlighted on the TV screen. The 1-2-8digits, when activated, provide a zero logic pulse which must, in orderto be accommodated by type 7410 NAND gate 150, be deconverted intological ones. This is accomplished by three type 7404 invertors 144, 146and 148. When all three of the digits 1-2-8 which are selected from theoutputs of the decoders 138, 140 and 142 provide logical ones to gate150, the output of gate 150 produces a logical zero. This logical zerois fed to a pair of type 7400 NAND gates 154 and 156 which are arrangedto provide a flip-flop 152. The imposition of a logical zero on theinput of gate 154 causes its output to produce a logical one, which inturn activates the input of NAND gate 156, causing it to produce anoutput of a logical zero. There is, in effect, a switching actionproduced between gate 154 and 156. Once they have been put into a statewhere the input from gate 154 has gone to a logical zero, gates 154 and156 tend to stay that way until such time as they are restored by meansof a reset signal derived through type 7404 invertor 158 from syncgenerator 160. Upon production of a vertical sync pulse having a logicalone, invertor 158 converts this to a logical zero and applies it to gate156 causing flip-flop 152 to reset. The signal output from flip-flop 152is a symmetrical wave in which half the period during successivehorizontal drive pulses the wave form is positive and the remaining halfit is zero. This wave form is used to switch the video beam of thekinescope on or off at the horizontal center line 107, as shown in FIG.10, depending on whether the top or bottom half of the TV screen is tobe viewed.

As best shown in FIG. 10, whether "X" or "Y" adjustments are to be madeon the position of the hole (represented by 169) in the spinneretteplate is determined by the ratio of areas of halves of the hole to thecomplete hole. Such areas measurements are made as hereinbeforedescribed. To enable the measurement of either horizontal or verticalhalves to the complete hole, it is necessary to divide the arearepresented by the hole 169 into quadrants A, B, C and D. Thus, if avertical deviation from center line 107 is to be determined, the area ofAB or CD would be compared to the area of ABCD. On the other hand, if ahorizontal deviation from the center line 105 is to be determined, theareas of AC or BD would be compared to the area ABCD.

To accomplish such area measurements, adjacent quadrants AB, BD, CD orAC must be measured and compared to the complete hole ABCD. Thesequadrants may be selected by the system shown in FIG. 9. Leads 162 and164 from flip-flop 128 on the horizontal adjustment portion are used asinputs to type 7400 NAND gates 190 and 188, respectively. Leads 163 and165 from flip-flop 152 on the vertical adjustment portion are used asinputs to type 7400 NAND gates 182 and 180 respectively. To select theparticular quadrants to be viewed for a ratio comparison, a voltage isapplied to a second input to select NAND gates 180, 182, 188 and 190.For example, in the case where AC is to be viewed, both are in the lefthalf of the hole. Consequently, one of the NAND gates 188 or 190controls the left half. If, for example, lead 162 from flip-flop 128controls the left half, a voltage would be applied to the other input200 of NAND gate 190. Thus, the output of gate 190 would be a logicalzero. This zero input to type 7400 NAND gate 192, along with a logicalone from gate 188 (because inputs 164 and 202 are both zero) results ina logical one output from gate 192. Depending on whether a logical oneor zero is inposed on the other input 208 to NAND gate 194, the input toNAND gate 196 from gate 194 will result in an output of zero or one toNAND gate 196 to NAND gate 198.

The gating system from the vertical sync pulse generator is similar tothat just described for the horizontal zync pulse generator. Thus, leads163 and 165 from flip-flop 152 on the vertical adjustment portion areused as inputs to type 7400 NAND gates 180 and 182, respectively. Forexample, in the case where AB is to be viewed, both are in the top halfof the hole. Consequently, one of the NAND gates 180 or 182 controls thetop half. If, for example, lead 163 from flip-flop 152 controls the tophalf, a voltage would be applied to the other input 204 of NAND gate182. Thus, the output of gate 182 would be a logical zero. This zeroinput to type 7400 NAND gate 184, along with a logical one from gate 180(because inputs 165 and 206 are both zero) results in a logical oneoutput from gate 184. Depending on whether a logical one or zero isimposed on the other input 210 to NAND gate 186, the input to NAND gate196 from gate 186 will result in an output of zero or one to NAND gate196 to NAND gate 198.

The other input to gate 198, lead 212 is from the area dot counter.therefore, even though the area dot counter is counting dots in thecomplete hole area, the count being transmitted to the computer by line214 for ratio comparision will only be passed through gate 198 when sodirected by the circuitry just described. The result is that dot countsin the particular quadrants A, B, C and D selected is controlled by thepresence or absence of logical zeros or ones on control leads 200, 202,204, 206, 208 and 210. This may be controlled manually or by a properlyprogrammed computer.

Referring to FIG. 11, a basic circuit is illustrated for causing thestepping motors to move the spinnerette plate to the coordinate positionto center a particular hole on the television monitor by comparing thearea to one side of center with the area of the entire hole.

The pulsating video signal from gate 304 is applied at an input terminalto three gates 310, 312, and 314. Depending on the position of switch316, timer 302 supplies pulses in synchronization to one of the gates310, 312 or 314. The extreme counterclockwise position of switch 316 mayrepresent the position representing half of the horizontal pulses, thenext clockwise position may represent a position representing half ofthe vertical pulses and the extreme clockwise position. Thus, dependingon the position of switch 316 a number of pulses will be applied toeither gate 310 leading to the horizontal pulse counter 318, thevertical pulse counter 320, or the full pulse counter 322. Comparatorcircuit 324, by comparing the horizontal half-count to the full count,or by comparing the vertical half-count to the full count, to an idearatio of one-half will send the necessary pulses to either gate 326 (forhorizontal centering) or gate 328 (for vertical centering). Computer 330will then cause either pulse generator 322 or 334 to send out thenecessary number of pulses through line 336 or 338 to cause eitherstepping motor 28 or 30 (See FIGS. 4 and 5) to center the hole withrespect to the television screen.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

I claim:
 1. Method of determining the deviation of the image of asupported object from a predetermined position on a kinescope screen,said image being bright with respect to the rest of the picture areacomprising(a) generating a video signal of at least a single frameduration which includes the bright image such that the complete area tobe measured is encompassed, (b) applying the electrical signalrepresenting the bright image to a switching device, one input of whichis supplied with a switching signal having a frequency of at least 10times the line scan frequency of the video signal to divide the periodof scanning represented by the bright image into a series of pulses, theduration of the pulse series being controlled by the beginning andending of the signal representing the bright image, (c) electricallyapplying the output signal from said switching device to a digitalcounter, whereby the area of said bright image is measured in terms ofnumber of pulses counted, (d) forming at least one line of a X-Ycoordinate system on the kinescope screen to establish a referenceposition by intensifying predetermined pulse counts of said switchingsignal to form said line, (e) using said predetermined pulse counts toturn off or on the scan lines on one side of said coordinate line, and(f) counting the dots to one side of said line, whereby the area of saidside is determined in terms of dot count and the ratio of such dot counton one side of said line to the dot count for the entire bright imagecan be used to determine position of the bright image area with respectto said line.
 2. Method according to claim 1 which includes the steps ofmovably supporting said object and using a stepping motor connected tosaid support for imparting motion thereto.
 3. Method according to claim1 wherein said object is a spinnerette.
 4. Method according to claim 3wherein the holes of said spinnerette are illuminated.
 5. Method ofpositioning the image of a supported object on a kinescope screen, saidimage being bright with respect to the rest of the picture areacomprising(a) generating a video signal of at least a single frameduration which includes the bright image such that the complete area tobe measured is encompassed, (b) applying said signal representing thebright image to a switching device, one input of which is supplied witha switching signal having a frequency of at least 10 times the line scanfrequency of the video signal to divide the period of scanningrepresented by the bright image into a series of pulses, the duration ofthe pulse series being controlled by the beginning and ending of thesignal representing the bright image, (c) electrically applying theoutput signal from said switching device to a digital counter, wherebythe area of said bright image is measured in terms of number of pulsescounted, (d) forming at least one line of a X-Y coordinate system on thekinescope screen to establish a reference position by intensifyingpredetermined pulse counts of said switching signal to form said line,(e) using said predetermined pulse counts to turn off or on the scanlines on one side of said coordinate line, (f) counting the dots to oneside of said line, whereby the area of said side is determined in termsof dot count and the ratio of such dot count on one side of said line tothe dot count for the entire bright image can be used to determineposition of the bright image area with respect to said line, and (g)producing at least one electrical signal of a duration proportional tosaid ratio and applying said signal to means for moving said image in apredetermined direction until a selected position is reached.
 6. Methodaccording to claim 5 which includes the step of applying said electricalsignal to a stepping motor connected to said support for impartingmotion thereto.
 7. Method according to claim 5 wherein said movableimage is a spinnerette.
 8. Method of determining the deviation of theimage of a supported object from a predetermined position on a kinescopescreen, said image being bright with respect to the rest of the picturearea comprising(a) generating a video signal of at least a single frameduration which includes the bright image such that the complete area tobe measured is encompassed, (b) electrically applying said video signalto a quantizer having the ability to pass portions of said video signalabove a predetermined amplitude which correspond to said bright image,and to reject portions of said video signal below the predeterminedamplitude, (c) amplifying te output signal from said quantizer to alevel sufficient to trigger a digital logic element, (d) applying theelectrical signal representing the bright image to a NAND gate switchingdevice, one input of which is supplied with a switching signal having afrequency of at least 10 times the line scan frequency of the videosignal to divide the period of scanning represented by the bright imageinto a series of pulses, the duration of the pulse series beingcontrolled by the beginning and ending of the signal representing thebright image, (e) electrically applying the output signal from said NANDgate switching device to a digital counter, whereby the area of saidbright image is measured in terms of number of pulses counted, (f)forming at least one line of a X-Y coordinate system on the kinescopescreen to establish a reference position by intensifying predeterminedpulse counts of said switching signal to form said line, (g) using saidpredetermined pulse counts to turn off or on the scan lines on one sideof said coordinate line, and (h) counting the dots to one side of saidline, whereby the area of said side is determined in terms of dot countand the ratio of such dot count on one side of said line to the dotcount for the entire bright image can be used to determine position ofthe bright image area with respect to said line.
 9. Method ofpositioning the image of a supported object on a kinescope screen, saidimage being bright with respect to the rest of the picture areacomprising(a) generating a video signal of at least a single frameduration which includes the bright image such that the complete area tobe measured is encompassed, (b) electrically applying said video signalto a quantizer having the ability to pass portions of said video signalabove a predetermined amplitude which correspond to said bright image,and to reject portions of said video signal below the predeterminedamplitude, (c) amplifying te output signal from said quantizer to alevel sufficient to trigger a digital logic element, (d) applying theelectrical signal representing the bright image to a NAND gate switchingdevice, one input of which is supplied with a switching signal having afrequency of at least 10 times the line scan frequency of the videosignal to divide the period of scanning represented by the bright imageinto a series of pulses, the duration of the pulse series beingcontrolled by the beginning and ending of the signal representing thebright image, (e) electrically applying the output signal from said NANDgate switching device to a digital counter, whereby the area of saidbright image is measured in terms of number of pulses counted, (f)forming at least one line of a X-Y coordinate system on the kinescopescreen to establish a reference position by intensifying predeterminedpulse counts of said switching signal to form said line, (g) using saidpredetermined pulse counts to turn off or on the scan lines on one sideof said coordinate line, (h) counting the dots to one side of said line,whereby the area of said side is determined in terms of dot count andthe ratio of such dot count on one side of said line to the dot countfor the entire bright image can be used to determine position of thebright image area with respect to said line, and (i) producing at leastone electrical signal of a duration proportional to said ratio andapplying said signal to means for moving said image in a predetermineddirection until a selected position is reached.
 10. Apparatus fordetermining the deviation of an image from a predetermined position on akinescope screen, said image being bright with respect to the rest ofthe picture area comprising(a) means for generating a video signal of atleast a single frame duration which includes the bright image such thatthe complete area to be measured is encompassed, (b) a switching deviceelectrically connected to said means for generating a video signal, oneinput of which is supplied with a switching signal having a frequency ofat least 10 times the line scan frequency of the video signal to dividethe period of scanning represented by the bright image into a series ofpulses, the duration of the pulse series being controlled by thebeginning and ending of the signal representing the bright image, (c) adigital counter electrically connected to said switching device formeasuring the area of said bright image in terms of number of pulsescounted, (d) means for forming at least one line of a X-Y coordinatesystem on the kinescope screen to establish a reference position byintensifying predetermined pulse counts of said switching signal to formsaid line, (e) means responsive to said pulse counts for turning off oron the scan lines on one side of said coordinate line, and (f) means forcounting the dots to one side of said line, whereby the area of saidside is determined in terms of dot count and the ratio of such dot counton one side of said line to the dot count for the entire bright imagecan be used to determine position of the bright image area with respectto said line.
 11. Apparatus for positioning the image of a supportedobject on a kinescope screen, said image being bright with respect tothe rest of the picture area comprising(a) means for generating a videosignal of at least a single frame duration which includes the brightimage such that the complete area to be measured is encompassed, (b) aswitching device electrically connected to said means for generating avideo signal, one input of which is supplied with a switching signalhaving a frequency of at least 10 times the line scan frequency of thevideo signal to divide the period of scanning represented by the brightimage into a series of pulses, the duration of the pulse series beingcontrolled by the beginning and ending of the signal representing thebright image, (c) a digital counter electrically connected to saidswitching device for measuring the area of said bright image in terms ofnumber of pulses counted, (d) means for forming at least one line of aX-Y coordinate system on the kinescope screen to establish a referenceposition by intensifying predetermined pulse counts of said switchingsignal to form said line, (e) means responsive to said pulse counts forturning off or on the scan lines on one side of said coordinate line,and (f) means for counting the dots to one side of said line, wherebythe area of said side is determined in terms of dot count and the ratioof such dot count on one side of said line to the dot count for theentire bright image can be used to determine position of the brightimage area with respect to said line, and (g) means for producing atleast one electrical signal of a duration proportional to said ratio andapplying said signal to means for moving said image in a predetermineddirection until a selected position is reached.
 12. Apparatus accordingto claim 11 which includes means for applying said electrical signal toa stepping motor connected to said support for imparting motion thereto.13. Apparatus according to claim 11 wherein said movable image is aspinnerette.